Mapping the research landscape of Covid-19 from social sciences perspective: a bibliometric analysis.

COVID-19 has emerged as a widely researched topic and the academia has taken interest in the effects of COVID-19 in various sectors of human life and society. Most of the bibliometric research addresses scientific contributions in medicine, health, and virology related topics, with very little emphasis on social sciences. Therefore, to address this gap, a bibliometric analysis of research related to COVID-19 in the subject area of social sciences was performed on selected publications from January 2020 to mid-2021.

Integrative network analyses of wilt transcriptome in chickpea reveal genotype dependent regulatory hubs in immunity and susceptibility.

Host specific resistance and non-host resistance are two plant immune responses to counter pathogen invasion. Gene network organizing principles leading to quantitative differences in resistant and susceptible host during host specific resistance are poorly understood. Vascular wilt caused by root pathogen Fusarium species is complex and governed by host specific resistance in crop plants, including chickpea.

Deterministic Construction of Plasmonic Heterostructures in Well-Organized Arrays for Nanophotonic Materials.

Plasmonic heterostructures are deterministically constructed in organized arrays through chemical pattern directed assembly, a combination of top-down lithography and bottom-up assembly, and by the sequential immobilization of gold nanoparticles of three different sizes onto chemically patterned surfaces using tailored interaction potentials. These spatially addressable plasmonic chain nanostructures demonstrate localization of linear and nonlinear optical fields as well as nonlinear circular dichroism.

Nonlinear chiro-optical amplification by plasmonic nanolens arrays formed via directed assembly of gold nanoparticles.

Metal nanoparticle assemblies are promising materials for nanophotonic applications due to novel linear and nonlinear optical properties arising from their plasmon modes. However, scalable fabrication approaches that provide both precision nano- and macroarchitectures, and performance commensurate with design and model predictions, have been limiting. Herein, we demonstrate controlled and efficient nanofocusing of the fundamental and second harmonic frequencies of incident linearly and circularly polarized light using reduced symmetry gold nanoparticle dimers formed by surface-directed assembly of colloidal nanoparticles.

Plasmon-induced transparency in the visible region via self-assembled gold nanorod heterodimers.

The phenomenon of plasmon-induced transparency holds immense potential for high sensitivity sensors and optical information processing due to the extreme dispersion and slowing of light within a narrow spectral window. Unfortunately plasmonic metamaterials demonstrating this effect has been restricted to infrared and greater wavelengths due to requisite precision in structure fabrication. Here we report a novel metamaterial synthesized by bottom-up self-assembly of gold nanorods.

Large scale solution assembly of quantum dot-gold nanorod architectures with plasmon enhanced fluorescence.

Tailoring the efficiency of fluorescent emission via plasmon-exciton coupling requires structure control on a nanometer length scale using a high-yield fabrication route not achievable with current lithographic techniques. These systems can be fabricated using a bottom-up approach if problems of colloidal stability and low yield can be addressed. We report progress on this pathway with the assembly of quantum dots (emitter) on gold nanorods (plasmonic units) with precisely controlled spacing, quantum dot/nanorod ratio, and long-term colloidal stability, which enables the purification and encapsulation of the assembled architecture in a protective silica shell.

Plasmonic resonances in self-assembled reduced symmetry gold nanorod structures.

Self-assembled plasmonic Dolmen structures consisting of small gold nanorods (length = 50 nm and diameter = 20 nm) with a few nanometer gaps are observed to show coherent effects of super-radiance and characteristics of Fano resonance due to the significantly reduced symmetry of the structure. Relative to previous larger structures from top-down electron-beam lithography, the single crystallinity and atomically smooth surfaces of these self-assembled plasmonic structures result in 50% narrower resonances, and the small gaps with associated strong coupling enable observation of multiple dark and bright modes. By tilting the cap monomer with respect to the base dimer an order of magnitude increase in E-field enhancement at the Fano dip is obtained.

Surface assembly and plasmonic properties in strongly coupled segmented gold nanorods.

An assembly strategy is reported such that segmented nanorods fabricated through template-assisted methods can be robustly transferred and tethered to a pre-functionalized substrate with excellent uniformity over large surface areas. After embedding the rods, sacrificial nickel segments were selectively etched leaving behind strongly coupled segmented gold nanorods with gaps between rods below 40 nm and as small as 2 nm. Hyper-spectral imaging is utilized to measure Rayleigh scattering spectra from individual and coupled nanorod elements in contrast to common bulk measurements.

Orientation Sensing with Color Using Plasmonic Gold Nanorods and Assemblies.

Colorimetric analysis of broadband illumination scattered from isolated gold nanorods and reduced symmetry Dolmen structures provide a visible measure of the local nanoscale orientation of the nanostructures relative to the laboratory frame of reference. Polarized dark-field scattering microscopy correlated with scanning electron microscopy of low and high aspect ratio gold nanorods demonstrated accuracies of 2.3 degrees, which is a 5-fold improvement over photothermal and defocused imaging methods.